THE KLAASSENBOSCH ARBORETUM IS SITUATED IN THE KLAASSENBOSCH GREEN BELT, AND IS HERE DIVIDED IN THREE SECTIONS FOR PURPOSES OF DESCRIPTION.
The green belt is a narrow piece of land on two sides of a stream, a contributory of the Diep River. It is about 400 m long and the width varies between some 50 and 100 m. The altitude is 120 m at the top and 70 m at the bottom.
A few years
ago the top 60 metres had almost no indigenous trees, but many invaders
(see top
species list). It was decided 
to enrich the area by planting as many indigenous tree
and shrub species as could be found at nurseries. There were two reasons: i) as
an education project, it would allow the public to identify the species by
looking at the leaves, trunks, flowers and fruit, instead of having to rely on
pictures in books; and ii) it would introduce indigenous fruit into the area to
get a better balance of fauna and flora. (The invading poplars and blackwoods
offer very little to entice indigenous fauna into the area.)
The last five years a large number of indigenous trees have been planted in the top section. These plants cannot be expected to thrive, in view of the presence of the invaders. They cast a dense shadow, so that due to a lack of sunlight the trees grow too tall and have thin trunks. When they can grow faster in the spring and summer, the poplars have leaves, reducing the sunlight to a minimum. In the summer, the invaders suck up the ground water, leaving the sand so dry that the planted trees have to be watered regularly to top them from dying. In the winter the temperature is low, being on the southern tip of Africa, and the growth is again slow. The top section has another problem in the winter, namely to become water logged. Few trees can tolerate the high ground water level in winter. See top for a species list.
There are a
few small areas in the middle section where some indigenous trees manage to
self-propagate. In these patches
there are fortunately fewer invader trees. There are
also two streams that converge in the area.
An old wild almond tree (Brabejum stellatifolium) which manages to survive in the middle section in the shade of tall invading poplar and blackwood trees. See middle for a species list.
In the bottom
section, near the retention dam, many yellowwood trees were planted some twenty
years ago. Most are the Outeniqua (Afrocarpus falcatus, used to be Podocarpus)
but a few are locally indigenous, namely the ‘true’ yellowwood (Podocarpus
latifolius), which grows a lot slower. There are also examples of the other
two indigenous Podocarpus species, namely henkelii and elongatus.
There were some open areas with less shade from invaders, and therefore this
bottom section was enriched with some 15 species of locally indigenous trees.
See the bottom species list.